Noninductive gyro rotor



Feb. 26, 1946. F. D. BRADDoN 2,395,447

NON-INDUGTIVE GYRO ROTOR Filed March 14, 1942 v 2 Sheets-Sheet 1 ME 'M INVENTOR, FREDERICK DA BRADDON,

` Hls AT`TORNEY.

Feb. 26, 1946. F. D. BRADDoN 2,395,447

NON-INDUCTIVE GYRO ROTOR Filed March 14, 1942 2 Sheets-Sheet? INVENT'OR. FREDERICK D. BRADDON,

H |s AoRNEY.

f magnetic compass.

' Patented F eb. 26, 1946 UNIT-Eo STATES PATENT oFilicl-j 2,395,447. c 4 NoNrNnUcrrvE Grao ao'roa Frederick D. Braddon, Babylon, N. Y., asslgnor to Sperry Gyroscope Company, Inc., Brooklyn, N. Y., a corporation ot New York Application Merch 14, 1942, serial Nc. 434,771

'z claims.

My invention is equally useful whether the magneticcompass is Yin the form of the `usual pivoted magnetic needle or a form of flux type compass or. other earth inductor types. a spinning lwheel of conventional material is placed near any magnetic element, eddy currents are generated in the spinning conductor l in the flux field in the magnet. Field distortion and energy absorption results from this phe` nomena resulting in disturbance of the compass. In fact, a magnetic needle placed near a revolving conductorv will be caused to spin with the conductor. and therefore become useless as armagnetic compass.

Many attempts have been made to construct gyro rotors of various non-conducting materials but the low specific gravity, the low tensile strength and the poor quality -of these materials have prevented the successful use for this purpose.

According to my invention, I propose to retain a heavy metal as the main element of the rotor but to so design the same that eddy currents in all planes is eiectively prevented.

Referring4 to the drawings illustrating my invention,

Fig. 1 is a view showing my improved rotor employed on a stabilized magnetic compass'.

Fig.` 2 is a side elevation of the rotor.

Fig. 3 is a face view of the same, partly in section; taken on brokenline 3-3 of Fig. 1. v

Fig. 4 is an enlarged sectional Vview of-al por-` tion of the rotor..

Fig. 5 is a greatly enlarged view of a piece 'of the wire making up the rotor, and

Fig. 6 'is a vertical section of a modied form of stabilized compass.

According to my invention,-I place upon the rotor shaft I, which is preferably of hardened steel, a spool or frame 2 of fabricated non-conducting or plastic material,- such as Bakelite. Within the annular recess 3 of this spool, I Wind a continuous coil of copper or other heavy metal wire 4 which is preferably enameled as indicated at 5 to insulate each turnu from the adjacent' convolutions. Ihe two ends of the wire 6 are left Whenever disconnected so that current now within the rotor is limited to the diameter of the wire thus virtually preventing yeddy currents in any direction. 'Ihe ends ofthe wire may be anchored f I in the frame as shown in Fig. 3. z The wire is wound closely together, and to maintain balance and strength, the spaces between the wire im- `pregnated with suitable plastic material such as Bakelite varnish, which is preferably baked lo after being applied. This bonds the vvwires of the coilV together. The spool or frame is -shown as of substantial thickness at one. end Vin' the periphery of'which I provide serrations 8, thus providing teeth or buckets forthe interceptionot a spin'- ning jet or jets from one or more nozzles l0; It

is also shown as having an outwardly tapering channel.l This not only gives a. greater strength to the walls of the spool near their base where the strain is greaterbut also permits the wire annulus-toV become thicker toward the rim or periphery where vthe increased mass is more effective in increasing the moment of inertia of the rotor. Y

In Fig. 1 the rotor is shown as forming the gyro rotor of a'gyroscopic stabilizer or articial horizon which stabilizes the magnetic compass I I pivoted therein on upper and lower vertical pivots l2 and I3. the design selected for illustration being similar to that shown in the prior patent to Elmer A. Sperry, No. 1,993,864, dated February 24, 1932. It is obvious, however, that my rotor design is adapted for any type of magnetic compass-gyroscope combination including gyro mag- -n'etic compasses, stabilized ux valve Compasses,

etc., as abovepointed out. In my improved rotor l design, the net density is much greater than the heaviest glass -or other non-conductor `and the heavier portion is near the riman the lighter portion near the center whereby a high moment 40 of inertia is obtained.

would not only have a high moment of inertia,

`but -would have a much greater factor of safety than a cast metal rotor or one made of powdered tungsten or the like, drawn `tungsten wire having a greater tensilestrength. A

'My improved rotor is shown in Fig. 6 as incorporated in a stabilized magnetic compass oi.' the top reading type. .In this `figure therotor 2 is mounted for spinning about a vertical axis in pivots l5, I6 within the rotor bearingcase l1 which in turn is mounted for oscillation about a horizontal axis on trunnions I8, I8' in bearings within the glmbal ring I9. The gimbal ring is `pivoted for oscillation about a horizontal axis at right angles to axis IB-I8 within the outer frame 20 by means of pivots, not shown. Air is withdrawn from the outer casing 20 through pipe 25 and the atmospheric air is introduced through said hollow trunnions, including -trunnions I8, yI 8', to supply air to the spinning jets I0, as before, and the exhaust air led down through apertures 2| into the hollow extension 22 from whence it emerges through gravitationally controlled ports 23 to erect the gyroscope, as Well understood in the art.v n top ofthe casing I1 isrpivoted in upper and lower pivots I2' and I3' a magnetic needle II' and on the pivot pin of the needle I mount a compass 'indicator which may be in the form of a pointer 2l readable upon an angular card 25. By virtue of my improved rotor, the compass needle may be mounted directly over the rotor without causing disturbance of the needle.

As many changes could be made in the above construction and many apparently widelydiierent embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative andnot in a limiting sense.

What is claimed is:

l, A gyroscopic rotor comprising a spool of insulating material having an annular depression and a winding of insulated open-circuited wire substantially filling said depression.

2. A gyroscopic rotor comprising a spool of insulating material having an annular depression, a serrated rim, and awinding of insulated opencircuited wire substantially filling said depression.

tapered so that itis thicker near the center thanv at the rim.

6. A gyro rotor structure comprising-a shaft, an open-circuited, insulated wire wound to provide a coil shaped generally in the form of a hollow circular cylinder with the wire bonded together to form a unitary mass, said coil being mounted on said shaft with the longitudinal axis of the coil and the axis of the shaft in coincidence.

7. A gyro rotor structure comprising a shaft, a

spool mounted on said shaft, and an open-circuited, insulated wire wound on said spool to provide a coil shaped generally in the form of a hollow circular cylinder arranged `in concentric relation to the axis of the shaft.

FREDERICK D. BRADDON. 

